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st: Re: Need help with agriculture split-plot (not Kirk's definition) - got it


From   Marta García-Granero <mgarciagranero@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   st: Re: Need help with agriculture split-plot (not Kirk's definition) - got it
Date   Mon, 18 Feb 2013 18:15:37 +0100

(ashamed)

Sorry, I found out for myself, I had forgotten the dash (/):

anova chloro blocks nitrogen/blocks#nitrogen  years nitrogen#years

Did the trick

"plots" was not needed, after all.

So much to  learn yet...

Regards,
Marta

El 18/02/2013 18:00, Marta García-Granero escribió:
Hi:

I am badly stuck trying to translate some SPSS syntax to Stata. I am trying to set the ANOVA model for an agriculture split-plot, as described in Kuehl's "Design of Experiments" 2nd ed., chapter 14, with different error terms for blocks & whole plots factor (error 1), and sub-plot factor & interaction (error 2).

The closest I got to Table 14.3 is this:

plots    blocks    nitrogen    years    chloro
1    1    1    1    3.8
1    1    1    2    5.3
1    1    1    3    5.9
2    2    1    1    3.9
2    2    1    2    5.4
2    2    1    3    4.3
3    1    2    1    5.2
3    1    2    2    5.6
3    1    2    3    5.4
4    2    2    1    6.0
4    2    2    2    6.1
4    2    2    3    6.2
5    1    3    1    6.0
5    1    3    2    5.6
5    1    3    3    7.8
6    2    3    1    7.0
6    2    3    2    6.4
6    2    3    3    7.8
7    1    4    1    6.8
7    1    4    2    8.6
7    1    4    3    8.5
8    2    4    1    7.9
8    2    4    2    8.6
8    2    4    3    8.4

insheet using "kuehlCh14splitplot", double tab
label define source 1 "ureic" 2 "ammonium" 3 "IBDU" 4 "ureic(S)"
label values nitrogen source
label define time 1 "2 years" 2 "5 years" 3 "8 years"
label values years time
anova chloro blocks nitrogen  years nitrogen#years plots|blocks#nitrogen

This used to work with SPSS, since it automatically sets as error term for a given factor any term nested inside it.

The SS, df & MS are correct, but I don't know how to force that the F values for blocks and nitrogen are computed using plots|blocks#nitrogenas error term.

My ANOVA table:

                           Number of obs =      24 R-squared =  0.9648
Root MSE = .463231 Adj R-squared = 0.8988

                  Source |  Partial SS    df MS           F Prob > F
----------------------+----------------------------------------------------
                   Model |  47.0629167    15 3.13752778 14.62     0.0003
                         |
                  blocks |  .510416667     1 .510416667 2.38     0.1616
                nitrogen |  37.3245833     3 12.4415278 57.98     0.0000
                   years |  3.81583333     2 1.90791667 8.89     0.0093
          nitrogen#years |  4.15416667     6 .692361111 3.23     0.0646
   plots|blocks#nitrogen |  1.25791667     3 .419305556 1.95     0.1996
                         |
                Residual |  1.71666667     8  .214583333
----------------------+----------------------------------------------------
                   Total |  48.7795833    23  2.12085145

My goal:

                           Number of obs =      24 R-squared =  0.9648
Root MSE = .463231 Adj R-squared = 0.8988

                  Source |  Partial SS    df MS           F Prob > F
----------------------+----------------------------------------------------
                   Model |  47.0629167    15  3.13752778
                         |
                  blocks |  .510416667     1 .510416667 0.510/0.419=1.218
nitrogen | 37.3245833 3 12.4415278 12.442/0.419=29.69
                   years |  3.81583333     2 1.90791667 8.89     0.0093OK
nitrogen#years | 4.15416667 6 .692361111 3.23 0.0646 OK plots|blocks#nitrogen | 1.25791667 3 .419305556 --> This should be Error for blocks&nitrogen
                         |
                Residual |  1.71666667     8  .214583333
----------------------+----------------------------------------------------
                   Total |  48.7795833    23  2.12085145

Any clues?

Thanks in advance,
Marta GG


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